1. Technical Field
The present disclosure relates to an electronic package, and more particularly, to a thin-type electronic package and a conductive structure thereof.
2. Description of Related Art
Along with the rapid development of electronic industries, electronic products are developed toward the trend of miniaturization and multi-function. Accordingly, various types of packages have been developed.
Generally, electronic elements of sensor elements and camera lenses are packaged to form wire-bonding or COB (Chip on Board) type package structures.
FIG. 1A is a schematic cross-sectional view of a conventional wire-bonding type package structure 1. Referring to FIG. 1A, the conventional wire-bonding type package structure 1 has a substrate 10, an electronic element 13 disposed on the substrate 10, and an encapsulant 18 formed on the substrate 10 and encapsulating the electronic element 13.
A first circuit layer 11 and a second circuit layer 12 are formed on upper and lower sides of the substrate 10, respectively, and a plurality of conductors 14 such as conductive through holes or conductive vias are formed in the substrate 10 for electrically connecting the first circuit layer 11 and the second circuit layer 12. Further, a first insulating layer 16 is formed on the upper side of the substrate 10, and portions of the first circuit layer 11 are exposed from the first insulating layer 16. A second insulating layer 17 is formed on the lower side of the substrate 10, and portions of the second circuit layer 12 are exposed from the second insulating layer 17. Furthermore, a plurality of conductive elements 15 are formed on the exposed portions of the second circuit layer 12.
The electronic element 13 is disposed on the upper side of the substrate 10 and electrically connected to the first circuit layer 11 through a plurality of gold wires 130. The electronic element 13 is a sensor element, which has a sensing area 131 formed on an upper surface thereof for fingerprint identification.
The electronic element 13 and the gold wires 130 are encapsulated by the encapsulant 18.
In the conventional wire-bonding type package structure 1, the sensing area 131 is covered by the encapsulant 18. The encapsulant 18 covering the sensing area 131 is required to have a very small thickness d with high precision so as to ensure effective sensing of the electronic element 13.
However, the gold wires 130 have a certain wire loop, and the molding process needs a sufficient height to allow the electronic element 13 to be uniformly encapsulated by the encapsulant 18. As such, the thickness of the encapsulant 18 is difficult to control and thinning of the wire-bonding type package structure 1 cannot be achieved.
FIG. 1B is a schematic cross-sectional view of a conventional COB type package structure 1′. Referring to FIG. 1B, the conventional COB type package structure 1′ has a substrate 10′, an electronic element 13 of a camera lens disposed on the substrate 10′, a transparent element 19 disposed on the electronic element 13, and an encapsulant 18 formed on the substrate 10′ and encapsulating the electronic element 13 and the transparent element 19.
The structure of the substrate 10′ can be referred to the structure of FIG. 1A.
The electronic element 13 is disposed on an upper side of the substrate 10′ and electrically connected to the substrate 10′ through a plurality of gold wires 130. The electronic element 13 has a sensing area 131 formed on an upper surface thereof for light sensing.
The transparent element 19 is disposed on the upper surface of the electronic element 13 through a plurality of support members 190 and covers the sensing area 131 of the electronic element 13.
The encapsulant 18 is made of a non-transparent material. The encapsulant 18 is formed on the upper side of the substrate 10 and encapsulates the transparent element 19, the electronic element 13 and the gold wires 130. An upper surface of the transparent element 19 is exposed from the encapsulant 18.
In the conventional COB type package structure 1′, the camera lens is required to be thinned. However, since the electronic element 13 is attached to the substrate 10′ and the transparent element 19 is disposed on the electronic element 13 through the support members 190, it is not easy to thin the COB type package structure 1′.
Accordingly, through silicon via (TSV) technologies are used to overcome the above-described drawbacks. FIG. 1C is a schematic cross-sectional view of a conventional light-sensing package structure 1″. Referring to FIG. 1C, the conventional light-sensing package structure 1″ has a silicon substrate 10″ and a transparent element 19′ disposed on the silicon substrate 10″.
A first circuit layer 11 and a second circuit layer 12 are formed on upper and lower sides of the silicon substrate 10″, respectively, and a plurality of conductive through silicon vias 100 are formed in the silicon substrate 10″ for electrically connecting the first circuit layer 11 and the second circuit layer 12. Further, a sensing area 131 is formed on the upper side of the silicon substrate 10″. An insulating layer 17′ is formed on the lower side of the silicon substrate 10″, and portions of the second circuit layer 12 are exposed from the insulating layer 17′. Further, a plurality of conductive elements 15 are formed on the exposed portions of the second circuit layer 12.
The transparent element 19′ is attached to the upper side of the silicon substrate 10″ through an adhesive layer 190′ and covers the sensing area 131.
However, the conductive through silicon vias 100 are difficult to fabricate and integrate and have a high fabrication cost, especially when they are applied in electronic elements of sensor elements and camera lenses.
Therefore, how to overcome the above-described drawbacks has become critical.